Catheter Introducer System

ABSTRACT

A catheter introducer system is provided with a catheter sheath having a valve providing for a friction fit around a catheter. The friction fit is selectively adjustable to vary between a first configuration for longitudinal movement of the catheter through the valve and a second configuration for holding the catheter longitudinally in place. The valve may include a chuck to grip the catheter radially. The chuck may include an annular base and an opposed annular clamp, and a washer disposed between the base and the clamp. At least one of the base and the clamp may include a beveled surface that forces the washer radially inwardly as the base and the clamp are drawn together. The system also includes one or more dilators layered within the sheath. One or more of the dilators may include a preformed arcuate portion configured to access a targeted branched vessel. The layered dilators and sheaths are typically softer and more hydrophilic proceeding from the innermost dilator out to the sheath. The dilator may be reinforced by a wire embedded in the body of the dilator. The distal tip of the sheath may be stiffened by a ring affixed adjacent the distal end. The sheath may include in the innermost dilator a trocar formed of a flexible, hollow outer wire and an inner stiff needle, which can extend beyond the wire for piercing and be withdrawn to relax the wire for advancement of the dilator.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent application Ser. No. 11/656,898, filed Jan. 22, 2007 and entitled “Catheter Introducer System”; which is a continuation of U.S. patent application Ser. No. 10/352,326, filed Jan. 27, 2003 and entitled “Catheter Introducer System”, now U.S. Pat. No. 7,166,088, both of which are incorporated herein by reference.

BACKGROUND

Catheters typically are inserted into a blood vessel through a sheath which is fixed in place relative to the blood vessel. The sheath protects the vessel and adjacent derma around the point of insertion while the catheter is advanced and withdrawn as necessary for the particular treatment being applied. The sheath is prepared for insertion by first placing a dilator within the lumen of the sheath and a needle or pointed wire within the lumen of the dilator. The needle or wire is used to pierce the derma and the blood vessel's wall and then is advanced into the blood vessel's lumen. Then the dilator is advanced along the wire without moving the needle or wire so that the tip of the dilator passes through the derma and blood vessel wall, expanding the diameter of the opening into the blood vessel.

At this point, with the dilator tip within the blood vessel lumen, the needle or wire may be withdrawn from the blood vessel. The sheath may then be advanced along the dilator, holding the dilator stationary, until the tip of the sheath is within the blood vessel's lumen. The sheath typically also expands the opening into the blood vessel. Once the sheath is in the blood vessel at a suitable location, the dilator may be withdrawn and the sheath braced in position, for example by taping the sheath to the patient's arm or leg adjacent the point of insertion. Then, the catheter is inserted through the sheath and into the blood vessel and maneuvered as necessary to provide the desired treatment.

Occasionally, it is desirable for a catheter introducer to navigate a tortuous or branched vessel, for example to access a contralateral artery for peripheral intervention. For example, access to the renal and contralateral iliac arteries from either an iliac or brachial access. Typically, a catheter having a preformed shape (such as an acute bend at the tip) is used. However, using a preformed catheter requires multiple catheter exchanges, thereby increasing the risk of human error and/or infection by increasing the motions and parts required to be removed and inserted into the patient to provide the desired treatment.

The catheter's outer diameter (o.d.) in such a system is limited by the inner diameter of the sheath, which in turn is limited by the expansion provided by the dilator. A typical dilator-sheath introducer provides a dilator lumen allowing only a 3-French or 0.038 inch o.d. wire, and the dilator must be expand outwardly relatively abruptly to reach even a modest outer diameter. The sheath lumen then is the same size as the outer diameter of the dilator, and typical size is only a 9-French or 0.118 inch, thus limiting the o.d. of the catheter to 9-French, which limits the types and capabilities of the catheters that can be used with such an introducer.

The dilator and sheath are typically formed of a plastic material and the tips of the dilator and sheath are sometimes damaged by insertion into the blood vessel. This may cause trauma to the derma and blood vessel, or require a second needle insertion if the tip is damaged to the extent it prevents suitable insertion.

The sheath typically includes an elastic collar adjacent a proximal end, through which the catheter is inserted. Such elastic collars are typically designed to allow the catheter to be advanced and withdrawn while providing some deterrence to blood leaking out through the sheath between the washer and the catheter. However, blood leakage past the washer is sometimes significant, causing unwanted complications to the catheterization procedure.

SUMMARY

A catheter introducer system is provided for inserting a sheath into a human blood vessel to provide a channel for a catheter to be moved within the blood vessel and to be held in a fixed position with minimum blood loss through the sheath. The catheter introducer system may include a trocar or other pointed instrument, such as a needle or pointed wire, for initially piercing the derma and the wall of the blood vessel. One or more dilators may surround the trocar and be sequentially inserted into the blood vessel after the trocar. The sheath surrounds the outermost of the dilators and is inserted last into the blood vessel. After removal of the trocar and dilator(s), the catheter may be inserted into the sheath and maneuvered within the blood vessel as necessary for the desired treatment. In some embodiments of a catheter introducer system, one or more dilators may have a preformed curvature and/or arcuate portion configured to navigate a targeted branched or tortuous area of a vessel.

When the catheter is at a desired location, it may be fixed longitudinally in place and blood loss through the sheath minimized by selective tightening of a hemostasis valve that includes a chuck that radially grips the catheter. The chuck may include a washer held between a base and a clamp and tightened therebetween, with beveled surfaces on the base, clamp, and/or the washer to provide for radial tightening of the chuck on the catheter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a catheter introducer system according to the present invention, including a dilator, a sheath, and a trocar.

FIG. 2 is an isometric view of the catheter introducer system as shown in FIG. 1, the system in this embodiment including two dilators.

FIG. 3 is an isometric view of the catheter introducer system as shown in FIGS. 1 and 2, the system in this embodiment including three dilators.

FIG. 4 is an isometric, exploded view of a proximal end of a sheath in accordance with the present invention, including a hemostasis valve with a chuck for variably gripping a catheter, the chuck including a base, a clamp coupled to the base by a threaded engagement, and a washer disposed between the base and the clamp.

FIG. 5 is a cross-sectional view of the proximal end of the sheath shown in FIG. 4, with the catheter inserted through the sheath and the washer therein, the clamp positioned to allow the catheter to move longitudinally through the sheath.

FIG. 6 is a cross-sectional view of the sheath as in FIG. 5, with the clamp positioned to tighten the washer onto the catheter.

FIG. 7 is a close-up pictorial view of the distal tip of the trocar of the catheter introducer system, showing an outer, hollow wire, an inner needle within the lumen of the wire and including a beveled tip extending out of the wire, and a boot at the tip of the wire.

FIG. 8 is a pictorial view of the trocar of FIG. 7 with the inner needle withdrawn into the wire and the boot closing to seal off the lumen of the wire.

FIG. 9 is a close-up end view of an alternative embodiment of the trocar of the catheter introducer system, showing a shutter at the tip of the wire that is open and a needle within the opening of the shutter.

FIG. 10 is a pictorial view of the trocar in the extended configuration shown in FIG. 9.

FIG. 11 is an end view of the trocar of FIG. 9 with the needle withdrawn into the wire and the shutter closed.

FIG. 12 is a pictorial view of the trocar in the withdrawn configuration of FIG. 11.

FIG. 13 is a side, cross-sectional view of the trocar of FIGS. 7-12 with the needle and wire tip inserted through the derma and into the blood vessel lumen of the patient, with the needle tip still extending out of the distal opening of the wire.

FIG. 14 is a side, cross-sectional view of the trocar as in FIG. 13 with the needle withdrawn from the wire and the wire returned to a flexible state within the blood vessel lumen.

FIG. 15 is an isometric view of a catheter introducer system according to the present disclosure, including a sheath and a dilator having a preformed arcuate curve.

FIG. 16 is an isometric view of the catheter introducer system as shown in FIG. 15, the system in this embodiment including two dilators, at least one of which having a preformed arcuate curve.

FIG. 17 is an isometric view of dilators A-D, each having a preformed arcuate curve in accordance with the present disclosure.

FIG. 18 is a flowchart of a sequence of operations that may be preformed in an exemplary method for accessing a branched target site in a vessel of a patient, in accordance with the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A catheter introducer system in accordance with the present invention is indicated generally at 10 in FIG. 1. Catheter introducer system 10 includes a sheath 12 having a generally elongate, typically cylindrical body 14 with a proximal end 16 and a distal end 18. Body 14 of sheath 12 is coupled at proximal end 16 to a housing 20. A central, typically cylindrical lumen 22 is defined within sheath 12 extending out through a distal opening 24 and a proximal opening 26. Sheath 12 is thus configured to receive a catheter 28 (FIG. 5) for longitudinal movement through and torsional movement within lumen 22.

Body 14 of sheath 12, is typically composed substantially of a flexible material, such as a plastic, polymeric material, preferably a hydrophilic material. Body 14 may include a reinforcement, such as stainless steel ring 30, to prevent buckling or crimping of distal end 18 at opening 24 when sheath 12 is inserted into a human blood vessel. The stainless steel ring 30 on the outermost sheath is radiopaque, as would be understood by those of ordinary skill in the art.

Catheter introducer system 10 further includes a first dilator 32 configured to be inserted into and disposed substantially within lumen 22 of sheath 12. First dilator 32 includes a generally elongate, typically cylindrical body 34 having a distal end 36 and a proximal end 38. Dilator 32 typically also includes a lumen interconnecting a distal opening 40 and a proximal opening 42, which typically is located in a housing 44 coupled to body 34 adjacent proximal end 38. Housing 44 may be provided with a luer lock fitting 46, which typically includes a double threaded engagement portion for coupling to mating devices.

Sheath 12 and dilator 32 typically are generally cylindrical, as noted above, typically with tapering adjacent distal ends 18, 36 to provide a smooth transition as the ends enter the blood vessel. Alternatively sheath 12 and dilator 32, and one or more intermediate dilators (to be described below), may be tapered substantially along the entire length of their bodies, preferably providing a more gradual, or additional, tapering as compared to the tapered distal ends. In either case, the sheath and dilators are preferably provided with a smooth transition between the body of one dilator and the distal end of the next outer sheath or dilator to prevent the distal end from snagging on the derma or blood vessel during insertion into the blood vessel.

Dilator 32 is preferably longer than sheath 12 so that distal end 36 and proximal end 38 of body 34 of dilator 32 extend out of the distal and proximal openings of sheath 12, as shown in FIG. 1. As an example, dilator 32 may be on the order of about 24 cm long and sheath 12 may be in the range of about 16 cm to about 20 cm, with other lengths selectable as appropriate for a particular application.

Catheter introducer system 10 may also include a trocar 48 inserted through dilator 32 and including a distal end 50 with a sharp, pointed tip 52. Trocar 48 is inserted through dilator 32 to create the initial entrance through the derma and into the blood vessel, and trocar 38 then is withdrawn after distal end 36 of dilator 32 is advanced into the blood vessel.

As shown in FIG. 2, catheter introducer system 10 may include a second, intermediate dilator 54 between the first dilator 32 and sheath 12. Second dilator 54 typically includes a generally elongate, substantially cylindrical body 56 with a distal end 58 and a proximal end 60.

A housing 62 is coupled to body 56 adjacent proximal end 60. A central lumen, similar to that for sheath 12 and first dilator 32 interconnects a distal opening 64 and a proximal opening 66.

Second dilator 54 preferably has a length greater than that of sheath 12 and less than that of first dilator 32. Thus, if first dilator 32 is about 24 cm, second dilator 54 is about 20 cm and sheath 12 is about 16 cm in length. The lengths of all the components of the catheter introducer system may be adapted for the particular application.

Preferably the dilator(s) and sheath are formed of less stiff, more flexible material as one progresses from innermost to outermost. E.g., first dilator 32 may be formed with the most stiff material, and may include a reinforcement, such as a wire 68 (FIG. 1), embedded or otherwise affixed to the material in a coil, web, or other suitable pattern to provide a stiffener. Second dilator 54 is typically formed of a less stiff material, while sheath 12 is formed of a still softer material so that the sheath/dilator bodies tend to be less traumatic to the blood vessel as they get larger. Second dilator, and other intermediate dilators, and sheath are typically progressively more hydrophilic as one proceeds outwardly. Ring 30, described above, helps to insure that the soft material of sheath 12 will not buckle or flare if the sheath tip catches or snags on the derma on insertion into the blood vessel. A ring may also be provided on the tips of one or more of the dilators in addition to or instead of on sheath 12.

With a two-dilator/one-sheath system, some typically available inner diameters (i.d.) in French sizes are shown in the following table:

Two-dilator/one-sheath First dilator Second dilator Sheath i.d. i.d. i.d. Ex. 1 3 4 5 Ex. 2 3 5 6 Ex. 3 3 5 7 Ex. 4 3 5 8 Ex. 5 3 5 9 Ex. 6 3 8 16

Other sizes may be used as appropriate for a particular application.

As shown in FIG. 3, catheter introducer system 10 may include a third, intermediate dilator 70 between the second dilator 54 and sheath 12. Second dilator 70 typically includes a generally elongate, substantially cylindrical body 72 with a distal end 74 and a proximal end 76. A housing 78 is coupled to body 72 adjacent proximal end 76. A central lumen, similar to that for the sheath and the first and second dilators interconnects a distal opening 80 and a proximal opening 82.

Third dilator 70 is preferably intermediate in length, in softness, and in hydrophilicity between second dilator 54 and sheath 12. With a three-dilator/one-sheath system, some typically available inner diameters (i.d.) in French sizes are shown in the following table:

Three-dilator/one-sheath First dilator Second dilator Third dilator Sheath i.d. i.d. i.d. i.d. Ex. 7 3 5 7 10 Ex. 8 3 5 9 11 Ex. 9 3 5 9 12 Ex. 10 3 5 9 13 Ex. 11 3 5 9 14 Ex. 12 3 5 9 15 Ex. 13 3 5 9 16 Ex. 14 3 5 9 17 Ex. 15 3 5 9 18

Other sizes may be used as appropriate for a particular application.

It will be seen from the foregoing that the system may include any number of dilators to reach a desired sheath size, and, for example, a four-dilator/one-sheath system could use the following sizes:

Four-dilator/one-sheath First dilator 2nd dilator 3rd dilator 4th dilator Sheath i.d. i.d. i.d. i.d. i.d. Ex. 16 3 5 9 12 19 Ex. 17 3 5 9 12 20 Ex. 18 3 5 9 12 21 Ex. 19 3 5 9 12 22 Ex. 20 3 5 9 12 23 Ex. 21 3 5 9 15 24 Ex. 22 3 5 9 15 26 Ex. 23 3 5 9 15 28

Other sizes may be used as appropriate for a particular application.

Sheath 12 as shown in FIGS. 1-3 includes a side branch or arm 84 in housing 20, which is commonly used for the introduction of intravenous fluid or medicine during a catheterization procedure. As shown in FIGS. 2 and 3, second dilator 54 includes a side branch 86 in housing 62 and third dilator 70 includes a side branch 88 in housing 78. Although the term dilator is commonly used to refer to a device without a side branch, FIGS. 2 and 3 illustrate that dilator, as used herein, can refer to a device either with or without a side branch, and the catheter introducer system may be used with sheaths and dilators including any combination of side branches or lack thereof.

As best seen in FIGS. 4-6, housing 20, which may be identical in the following respects to the housings on any or all of the dilators, includes a hemostasis valve, indicated generally at 90, for preventing blood leaks between catheter 28 and housing 20. Such blood leaks typically flow along inner lumen 22 and out proximal opening 26. Housing 20 is shown in FIGS. 4-6 with all of the smaller dilators and the trocar withdrawn, and, in FIGS. 5 and 6 with catheter 28 inserted.

Hemostasis valve 90 includes a chuck 92 for selectively gripping radially onto catheter 28. Chuck 92 includes a collar, such as flexible, elastomer washer 94, defining an opening 96 configured to receive catheter 28 therethrough. Preferably washer 94 fits snugly around catheter 28 in a first configuration, shown in FIG. 5, allowing catheter 28 to be moved longitudinally therethrough.

Valve 90 thus provides for a friction fit around the catheter. The friction fit is selectively adjustable to vary between a first configuration for longitudinal movement of the catheter through the valve and a second configuration for holding the catheter longitudinally in place. A physician operating the catheter introducer system may selectively switch valve 90 to the second configuration, typically when catheter 28 is in a desired location within the blood vessel to perform a catheter procedure, such as installing a stent or applying RF energy at the distal tip of the catheter.

Preferably the physician selects the second configuration by grasping a threaded cap 98 of valve 90, and rotating to tighten cap 98 onto a threaded portion 100 of housing 20. Such tightening of cap 98 drives a clamp 102 within cap 98 to squeeze washer 94 between clamp 102 and a base 104 in housing 20. Preferably, clamp 102 is a sloped annular ring providing a beveled surface within cap 98. The ring preferably has an outer circumference 106 generally coincident with an outer circumference of washer 92, and an inner circumference 110 generally coincident with an inner circumference 112 of washer 92. Preferably, base 104 is a sloped annular ring, providing a beveled surface that includes an outer circumference 114 and an inner circumference 116 coincident with corresponding circumferences of the washer and the clamp. Inner circumference 112 of washer 92 is nominally at least as large as the o.d. of catheter 28, although it can be smaller to provide a tighter nominal friction fit.

In the second configuration, shown in FIG. 6, cap 98 has been tightened onto housing 20 so that clamp 102 and base 104 are closer together than a nominal width of washer 92. Thus washer 92 is pressed radially inwardly by the sloping faces of clamp 102 and base 104, which tends to reduce the washer's inner circumference 112 and to close opening 96, thereby tightening washer 92 onto catheter 28. Valve 90 may be selectively adjusted by the physician to any degree of tightness, thereby allowing the physician to select an optimal combination of leakage prevention and ease of catheter longitudinal and torsional movement. Preferably, with cap 98 fully tightened, substantially no blood leaks between catheter 28 and washer 92 and catheter 28 is substantially locked longitudinally in place.

Washer 92 is shown in FIGS. 4-6 as a flat washer. Washer 92 may alternatively have one or two sloped or beveled surfaces which may correspond to the sloped faces of clamp 102 and base 104. A washer 118 with two sloped faces 120 is shown in FIG. 1 incorporated into a hemostasis valve, indicated generally at 122, on first dilator 32. Valve 122 operates in a manner generally similar to that of valve 90.

FIGS. 7-14 show embodiments of trocar 48, in particular the structure at distal end 50 of trocar 48. Trocar 48 may include a hollow, preferably flexible wire 124 defining a central lumen 126 extending out to a distal opening 128. A hollow, preferably stiff needle 130 provided with a sharp tip, such as beveled end 132, may be inserted in lumen 126. In an operative condition, as shown in FIG. 7, tip 132 will extend out of opening 128 of wire 124. A sealing mechanism, such as flexible cuff or boot 134 may be coupled to wire 124 at opening 128. Sealing mechanism 134 includes an opening 136 which stretches to allow needle tip 132 to extend through the sealing mechanism in the operative condition. Needle 130 includes a proximal end extending out of the proximal end of trocar 48, which extends out of proximal opening 42 of dilator 32 (see FIGS. 1-3). Needle 130 also includes a central lumen 138 extending from tip 132 to the proximal end.

As shown in FIGS. 13 and 14, the physician may use trocar 48 with needle tip 132 extending out of wire 124 to insert the trocar tip through the patient's derma and into the blood vessel. FIG. 13 shows that the flexible wire with the stiff needle inserted therethrough is stiff and insertable into the blood vessel along with the needle tip. The physician can verify that the needle tip is in the blood vessel by the blood that will flow into lumen 138 of needle 130 and out the proximal end.

Once the wire and needle are verified as inserted into the lumen of the blood vessel, the physician can pull on the proximal end of the stiff needle, withdrawing it from the trocar tip, as shown in FIG. 14, at which time wire 124 will again become flexible. The flexible wire presents a less dangerous and traumatic device within the blood vessel, as compared to a stiff wire or needle. The withdrawn needle is also shown in FIG. 8, where it can be seen that sealing mechanism 134 has closed to prevent further blood flow through trocar 48.

Another embodiment of a sealing mechanism is shown in FIGS. 9-12, where wire 124 includes adjacent opening 128 a shutter 140. A plurality of shutter vanes 142 may be mounted on hinges 144 and preferably may be nominally biased to a closed position (FIGS. 11 and 12). Shutter 140 can be opened by inserting tip 132 of needle 130 through the shutter, as is shown in FIGS. 9 and 10. The physician uses the embodiment of FIGS. 9-12 in the same manner as that of FIGS. 7 and 8, inserting the needle tip through the derma and into the lumen of the blood vessel and then withdrawing the needle, allowing the shutter to close and the wire 124 to go limp, as shown in FIGS. 13 and 14.

Turning now to FIG. 15, a catheter introducer system in accordance with the present disclosure, indicated generally at 200, may be configured to navigate a curve or directional change in a vessel and/or contralateral access of a branched vessel. The catheter introducer system 200 may include a sheath 202 having a generally elongate, typically cylindrical body 204 with a proximal end 206 and a distal end 208. The body 204 of the sheath 202 may be coupled at the proximal end 206 to a housing 210. The sheath 202 and/or the housing 210 may be configured substantially as described with reference to the embodiments of a housing shown in FIGS. 1-6.

A central, typically cylindrical lumen may be defined within sheath through a distal opening 212 and a proximal opening 214. The sheath 202 may thus be configured to receive a catheter (not shown) for longitudinal movement through and torsional movement within the lumen. The body 204 of the sheath 202 may be composed of a flexible material, such as a plastic, polymeric material and/or a hydrophilic material. The body 204 may include a reinforcement, such as a ring 216, to prevent buckling or crimping of the distal end 216 at the opening 212 when the sheath 202 is inserted into a vessel. The sheath 202 may taper at distal end 216 to provide a smooth transition as the distal end 216 enters a vessel.

The catheter introducer system 200 may further include a first preformed dilator 218 configured to be inserted into and disposed substantially within lumen of the sheath 202. The first preformed dilator 218 may include a distal end 220 and a proximal end 222. The preformed dilator 218 may taper at distal end 220 to provide a smooth transition as the distal end 220 enters the blood vessel. The first preformed dilator may also include a lumen interconnecting a distal opening 224 and a proximal opening 226, which may be located in a housing 228 adjacent the proximal end 222.

A generally cylindrical non-linear body 230 of the first preformed dilator 218 may be configured for insertion into a vessel and may include an arcuate portion 232 bent in a manner to enable the distal end 220 to be precisely located relative to a vessel, for example a target area in a branched vessel. The stiffness of the body 230 of the first preformed dilator 218 may be greater than the stiffness of the body 204 of the sheath 202.

The preformed curvature of the arcuate portion 232 is discussed in further with reference to FIG. 17. Generally, a preformed dilator in accordance with the present disclosure may have a predetermined curvature extending all or a portion of the dilator length between the proximal and distal ends. The arcuate portion and/or predetermined curvature(s) of the preformed dilator may be configured to navigate a branched vessel with minimal or no damage to the vessels. Preformed dilator lengths and shapes are infinitely variable and choice is based on the type and location of the target vessel.

As shown in relief in FIG. 15, some embodiments of the catheter introducer system 200 may further include a trocar 234 and/or a pointed instrument insertable through the first preformed dilator 218, having a distal end 236 with a sharp, pointed tip 238. The trocar 234 may have a stiffness that is greater than that of the first preformed dilator 218 such that when the trocar 234 is inserted into the first preformed dilator 218, the arcuate portion 232 is temporarily urged into a substantially elongate shape, as shown in relief in FIG. 15. The arcuate portion 232 of the first preformed dilator 218 may return to its preformed bent or non-linear shape when the trocar 234 is withdrawn. Some embodiments of the trocar 234 may be substantially configured as one or all of the embodiments of a trocar described with reference to FIGS. 7-14.

The catheter introducer system 200 for accessing a branched target site in a vessel may include a dilator assembly and/or a second, intermediate dilator between the first preformed dilator 218 and the sheath 202. For example as shown in FIG. 16, the catheter introducer system 200 may include a second preformed dilator 240 defining a generally non-linear body 242 having a distal end 244 and a proximal end 246 and an arcuate portion 247. The curvature of the non-linear body 242 of the second preformed dilator may be the same as or different than a first preformed dilator.

A housing 248 may be coupled to the body 242 adjacent the proximal end 246. A central lumen, similar to that for the sheath 202 and the first preformed dilator 218 may interconnect a distal opening 250 and a proximal opening 252. The second preformed dilator 240 may be disposed substantially within the lumen of the first preformed dilator 218 with the distal end 244 of the second preformed dilator 240 extending through the distal opening 224 of the first preformed dilator 218.

The dilators and sheath may be formed of less stiff, more flexible material as one progresses from innermost to outermost. For example, the first preformed dilator 218 may be formed with the stiffest material. The second preformed dilator 240 may be formed of a less stiff material, which the sheath 202 is formed of a still softer material so that the sheath/dilator bodies tend to be less traumatic to the vessel as they get larger. Additionally and/or alternatively, at least a portion of the dilator assembly may have a greater stiffness than at least a portion of a sheath, in accordance with the present disclosure. The second preformed dilator, and any other intermediate dilators, and sheath may be progressively more hydrophilic as one proceeds outwardly. A ring may be also provided on the tips of one or more of the dilators in addition to or instead of on the sheath.

Some embodiments of the catheter introducer system 200 may include a dilator assembly having three or more dilators. Any one or all of the dilators may include a preformed arcuate portion in accordance with the present disclosure. Additionally and/or alternatively, in some embodiments, the catheter introducer system 200 may include an intermediate dilator that may define a generally elongate body as described with reference to FIGS. 1-3.

Exemplary preformed dilators A-D, each having at least one arcuate portion are shown in FIG. 17. For example, FIG. 17A shows a preformed dilator 300 including a first straight proximal portion 302 extending from a proximal end 304 of the preformed dilator 300 and an arcuate portion 306 extending distally from the straight portion and bent in a manner to enable the distal end to be precisely located relative to a vessel. An arcuate portion in accordance with the present disclosure may have any shape including but not limited to a hook, an arch, a gradual curve, a sharp curve, etc.

In some embodiments, a distal end may extend distally from an arcuate portion. In other embodiments, one or more intermediate or divergent portions may extend between the arcuate portion and the distal end. The one or more intermediate portions may be bent or straight depending on the desired application. For example, the preformed dilator 300 includes a distal end 308 and a substantially straight intermediate portion 310 extending between the distal end 308.

Furthermore, the lengths of the dilator portions, such as the arcuate portion 306 and/or the straight proximal portion 302 may be chosen such that, when the preformed dilator 300 is inserted into the vasculature, the proximal portion 302 extends from the access site to adjacent the target branch area, with the arcuate portion 306 disposed along the target branch area with the distal end 308 engaged with the target branch area.

As described above, the predetermined configuration, shape, and/or curvature of an arcuate portion of a catheter introducer system, including a preformed dilator in accordance with the present disclosure, is infinitely variable. Selection of the shape and/or curvature of a predetermined arcuate portion is based on the type and location of the target vessel and/or branched target site in a vessel. Additionally and/or alternatively, an arcuate portion from a first preformed dilator and an arcuate portion of a second preformed dilator may combine to provide the desired shape for access of a branched target site in a vessel. An arcuate portion may include one or more curvatures and the one or more curvatures may be seamlessly blended. For example, the embodiments of the preformed dilator 300, 310, 312 and 314 shown in FIG. 17 A-D, include arcuate portions 306, 316, 318, and 320 having an increasing degree of curvature.

FIG. 18 is a flowchart of a sequence of operations that may be preformed in an exemplary method for accessing a branched target site in a vessel of a patient, in accordance with the present disclosure, indicated generally at 400, using a catheter introducer system including a sheath and a dilator assembly having a predetermined arcuate portion. A pointed instrument such as trocar may be initially introduced adjacent a branched target site and/or aortic bifurcation (402). The sheath and the dilator assembly may be inserted over the pointed instrument into the vessel (404) and then advanced over the pointed instrument such that the arcuate portion of the dilator assembly is in an area adjacent the branched target site (406). The arcuate portion of the dilator assembly may then be further advanced fully over the pointed instrument, such that a distal end of the dilator assembly is steered into the branched target site (408). The pointed instrument may be advanced past the distal end of the dilator assembly and into the target vessel. A catheter may then be inserted into the target vessel substantially as described above or any other method known in the art.

It is believed that the disclosure set forth above encompasses multiple distinct inventions with independent utility. While each of these inventions has been disclosed in its preferred form, the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the inventions includes all novel and non-obvious combinations and subcombinations of the various elements, features, functions and/or properties disclosed herein. No single feature, function, element or property of the disclosed embodiments is essential to all of the disclosed inventions. Similarly, where the claims recite “a” or “a first” element or the equivalent thereof, such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements.

It is believed that the following claims particularly point out certain combinations and subcombinations that are directed to one of the disclosed inventions and are novel and non-obvious. Inventions embodied in other combinations and subcombinations of features, functions, elements and/or properties may be claimed through amendment of the present claims or presentation of new claims in this or a related application. Such amended or new claims, whether they are directed to a different invention or directed to the same invention, whether different, broader, narrower or equal in scope to the original claims, are also included within the subject matter of the inventions of the present disclosure. 

1. A catheter introducer system comprising: a sheath defining a generally elongate body having a lumen, and a distal opening and a proximal opening communicating with the lumen; and a first preformed dilator defining a generally non-linear body having a distal end tapering inwardly to a narrower diameter at the tip, a proximal end, and at least one preformed arcuate portion; wherein the first dilator is disposed substantially within the lumen of the sheath such that the distal end of the first dilator extends through the distal opening of the sheath and the stiffness of the first dilator is greater than the stiffness of the sheath.
 2. The catheter introducer system of claim 1, wherein the body of the first dilator includes a substantially straight proximal portion and an arcuate portion extending distally from the proximal portion.
 3. The catheter introducer system of claim 2, wherein the body of the first dilator includes a divergent portion extending distally from the arcuate portion.
 4. The catheter introducer system of claim 1, further comprising a second preformed dilator defining a generally non-linear body having a distal end tapering inwardly to a narrower diameter at the tip, a proximal end, and at least one preformed arcuate portion; wherein the first dilator further includes an opening adjacent each end, and an open lumen communicating with the openings, and wherein the second dilator is disposed substantially within the lumen of the first dilator with the distal end of the second dilator extending through the distal opening of the first dilator.
 5. The catheter introducer system of claim 4, wherein the body of the second dilator includes a substantially straight proximal portion and an arcuate portion extending distally from the proximal portion.
 6. The catheter introducer system of claim 5, wherein the body of the second dilator includes a divergent portion extending distally from the arcuate portion.
 7. The catheter introducer system of claim 4, wherein the degree of curvature in the at least one arcuate portion of the body of the first dilator is different than the degree of curvature in the at least one arcuate portion of the body of the second dilator.
 8. The catheter introducer system of claim 4, wherein the stiffness of the sheath is less than the stiffness of the second preformed dilator.
 9. The catheter introducer system of claim 1, wherein the sheath includes a valve provided with an opening configured to receive a catheter therethrough, and a shutter adjacent the opening to provide for a friction fit around the catheter, the friction fit being selectively adjustable to vary between a first configuration for longitudinal movement of the catheter through the valve and a second configuration for holding the catheter longitudinally in place.
 10. The catheter introducer system of claim 9, wherein the shutter includes a plurality of shutter vanes manipulable to provide for the friction fit.
 11. A catheter introducer system for introduction of a catheter into a blood vessel comprising: a sheath defining a generally elongate body having a lumen, and distal and proximal openings communicating with the lumen and configured for insertion and longitudinal movement of the catheter there through; a dilator assembly including at least a first dilator and a second dilator, each having a distal end and a proximal end, an opening adjacent each end, and an open lumen communicating with the openings, the first dilator disposed substantially within the lumen of the sheath such that the distal end of the first dilator extends through the distal opening of the sheath, and the second dilator having a distal end tapering inwardly to a narrower diameter at the tip, the second dilator disposed substantially within the lumen of the first dilator with the distal end of the second dilator extending through the distal opening of the first dilator; wherein at least one of the first dilator and the second dilator is preformed to define a generally non-liner body including an arcuate portion.
 12. The catheter introducer system of claim 11, wherein the dilator assembly has a greater stiffness than the sheath stiffness.
 13. The catheter introducer system of claim 11, wherein the sheath further includes a housing coupled to the sheath body, the body and housing including a lumen configured for insertion and longitudinal movement of a catheter there through, the housing of the sheath defining a proximal end opposite the body of the sheath, the sheath including a valve coupled to the housing adjacent the proximal end of the housing, the valve further provided with an opening configured to receive the catheter there through and a shutter adjacent the opening, the shutter providing for a friction fit around the catheter, the friction fit being selectively adjustable to vary between a first configuration for longitudinal movement of the catheter through the valve and a second configuration for holding the catheter longitudinally in place.
 14. The catheter introducer system for introduction of a catheter into a blood vessel of claim 13, wherein the shutter includes a plurality of shutter vanes manipulable to provide for the friction fit.
 15. The catheter introducer system for introduction of a catheter into a blood vessel of claim 14, wherein the plurality of shutter vanes are mounted on hinges.
 16. The catheter introducer system for introduction of a catheter into a blood vessel of claim 11, further comprising a trocar inserted through a lumen of the second dilator, the trocar including a flexible, hollow outer wire, wherein the wire is provided with sufficient flexibility and length for insertion into and safe passage along the blood vessel for guidance of the catheter in the longitudinal movement of the catheter through the blood vessel, and a stiff, inner needle with a distal end extending beyond a distal end of the wire, the needle configured for piercing through a patient's derma and entering the blood vessel.
 17. A method for accessing a branched target site in a vessel of a patient, comprising: inserting a pointed instrument into the vessel, and guiding the pointed instrument to an area adjacent the branched target site; inserting a catheter introducer system over the pointed instrument into the vessel, wherein the catheter introducer system includes a sheath defining a generally elongate body having a lumen and distal and proximal openings communicating with the lumen, a dilator assembly defining a generally non-linear body having a distal end and a proximal end and a predetermined arcuate portion, wherein the dilator assembly is disposed substantially within the lumen of the sheath with the distal end of the dilator assembly extending through the distal opening of the sheath; passing the catheter introducer system over the pointed instrument such that the arcuate portion of the dilator assembly is in an area adjacent the branched target site; and advancing the arcuate portion of the dilator assembly over the pointed instrument into the branched target site.
 18. The method for accessing a branched target site in a vessel of a patient of claim 17, further comprising advancing the pointed instrument into the branched target site.
 19. The method for accessing a branched target site in a vessel of a patient of claim 17, wherein the dilator assembly includes at least a first dilator and a second dilator, each having a distal end and a proximal end, an opening adjacent each end and an open lumen communicating with the openings, the first dilator disposed substantially within the lumen of the sheath such that the distal end of the first dilator extends through the distal opening of the sheath, and the second dilator disposed substantially within the lumen of the first dilator with the distal end of the second dilator extending through the distal opening of the first dilator; wherein at least one of the first dilator and the second dilator is preformed to define a generally non-linear body including an arcuate portion.
 20. The method for accessing a branched target site in a vessel of a patient of claim 17, wherein the dilator assembly has a greater stiffness than the sheath. 